The present invention relates to a device for the detection and quantification of agglutinates capable of being formed, under the action of at least one reagent, by particles in suspension in a liquid.
It may be used whenever agglutinates are to be detected and quantified. However, it is particularly applicable in immunohaematology, particularly for the purpose of determining blood groups. In fact, it is known that blood groups are determined by seeking the existence in the blood of erythrocytic antigens. The immunocytological reactions, in the face of an antigen of a specific group, are translated by a phenomenon of agglutination of the red blood corpuscles if the latter belong to another group. These red cells may form either uniform agglutinates without free red cells, or some large agglutinates or a large number of small agglutinates.
Although the present invention is not limited in its applications to immunohaematology, it will be descibed hereinafter with more specific reference to this particular application.
A device for the detection and quantification of agglutinates includes a photodetector, a rotatable and translatable support comprising a transparent disc having pits therein, a pivotably supported syringe support which is automatically actuable to draw sample liquids and to dispense sample liquids into pits in the disc, such that each pit can be scanned by the photodetector having for example n detector elements across, and scanning each pit at a plurality of locations (for example, in step-by-step motion of the disc over the photodetector, an n number of times). The agglutinates are capable of being formed under the action of at least one liquid reagent by particles in suspension in doses of liquids to be tested which are contained in recipients formed in the rotatable support. The device comprises a radially disposed arrangement of a plurality n of photosensitive elements. The transparency of the bottoms of said recipients containing the agglutinates permits light passing through said bottoms of said recipients, the light being supplied by a light source overlying the rotatable support.
Said recipients are formed by pits distributed along radii of the transparent horizontal disc support and is adapted to rotate about the vertical axis of the disc. The spindle and disc are movable in m steps past the arrangement 35 n times for each recipient, thereby sensing a total of n.times.m locations of each individual recipient. An oscillating arm movable about a vertical axis by a support member, and having syringes for taking and restituting liquid doses is provided, to take such doses from reservoirs of reagents located within the range of movement of the oscillating arm. The arm takes liquids to be tested and deposits the liquid into said pits in the rotatable disc. The linear arrangement of photosensitive elements is permanently disposed at right angles to a diameter of the transparent disc and is in a plane parallel to a plane containing a lower surface of the disc. The axis of rotation of the disc is mounted to move in translation at right angles to said linear arrangement of photosensitive elements so that each recipient can be scanned at n.times.m points by appropriate translation of the disc relative to the photodetector elements.
Via its means for taking and restituting liquid doses, which may for example be syringes, the oscillating arm may thus introduce into each pit in the rotating disc a liquid to be tested and the corresponding reagent. After reaction, each pit is examined by the photosensitive element arrangement in the course of translation of the axis of the disc, the amplitude of which translation is sufficient for all the pits of a radius of the disc to be observed, each in m steps.
The oscillating arm advantageously bears as many taking and restituting means as a radius of the disc comprises pits, with the result that the oscillating arm fills all the pits of a radius at one time.
In an advantageous embodiment, the linear arrangement of photosensitive elements is disposed at right angles to the vertical plane passing through the vertical axes of the transparent disc and the oscillating arm, on the side of the disc axis opposite said oscillating arm, so that the disc must make a rotation through 180.degree. for a radius of pits filled with doses of liquids to be tested and with reagent to be read by said arrangement.
The reservoirs of reagents are preferably disposed permanently on one side of the vertical plane defined by the vertical axes of the oscillating arm and the disc, whilst the reservoirs of liquids to be tested are associated with conveyor means advancing them step by step, parallel to this vertical plane, but on the side opposite said reservoirs of reagents.
The arrangement of photosensitive elements may be of the type constituted by a bar of charge coupled diodes, generally designated by the letters CCD, DTC or CCPD. According to the invention, in which a rectilinear bar of n charge coupled devices is used, observation is effected with a view to detecting the possible agglutinates and during the relative movement of each transparent bottom of the recipient in m spaced apart, parallel positions of said bar, so as to form n.times.m points of observation distributed over a rectangular or square surface occupying the major part of the surface of said bottom. Of course, n may be chosen to be equal to m and the distance between two consecutive positions of observation of the bar is arranged to be equal to the distance between two CCDs of the bar. Thus, a square surface of the transparent bottom is totally covered. For example, the rectilinear bar comprises 256 CCD photodiodes, each having a definition of 25 .mu..sub.m, the video information being digitized in 256 grey levels, and the analyzed image represents a square centred on said transparent bottom and formed by 256 scans spaced apart by 25 .mu..sub.m.
For observing the agglutinates and for each recipient, n.times.m measures are thus obtained, distributed in m scans of n points.
The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: